12903 research outputs found
Sort by
A novel diagnostic gene region for distinguishing between two pest fruit flies: Bactrocera tryoni (Froggatt) and Bactrocera neohumeralis (Hardy) (Diptera: Tephritidae)
Get PDFBactrocera tryoni and Bactrocera neohumeralis are morphologically similar sibling pest fruit fly species that possess different biological attributes, geographic distributions, and host ranges. The need to differentiate between the two species is critical for accurate pest status assessment, management, biosecurity, and maintenance of reference colonies. While morphologically similar, adults may be separated based on subtle characters; however, some characters exhibit intraspecific variability, creating overlap between the two species. Additionally, there is currently no single molecular marker or rapid diagnostic assay that can reliably distinguish between B. neohumeralis and B. tryoni; therefore, ambiguous samples remain undiagnosed. Here we report the first molecular marker that can consistently distinguish between B. tryoni and B. neohumeralis. Our diagnostic region consists of two adjacent single nucleotide polymorphisms (SNPs) within the pangolin (pan) gene region. We confirmed the genotypes of each species are consistent across their distributional range, then developed a tetra-primer amplification refractory mutation system (ARMS) PCR assay for rapid diagnosis of the species. The assay utilizes four primers in multiplex, with two outer universal primers, and two internal primers: one designed to target two adjacent SNPs (AA) present in B. tryoni and the other targeting adjacent SNPs present in B. neohumeralis (GG). The assay accurately discriminates between the two species, but their SNP genotypes are shared with other nontarget tephritid fruit fly species. Therefore, this assay is most suited to adult diagnostics where species confirmation is necessary in determining ambiguous surveillance trap catches; maintaining pure colony lines; and in Sterile Insect Technique management responses
Effect of a Lactobacilli-Based Direct-Fed Microbial Product on Gut Microbiota and Gastrointestinal Morphological Changes
No full textThe calf’s gastrointestinal tract (GIT) microbiome undergoes rapid shifts during early post-natal life, which can directly affect calf performance. The objectives of this study were to characterise and compare differences in the establishment and succession of GIT microbiota, GIT morphological changes, and the growth of dairy calves from birth until weaned. Forty-four newborn Holstein-Friesian calves were randomly selected and assigned to Treatment (TRT) and Control (CON) groups. The TRT group calves received a once-daily dose of a direct-fed microbial (DFM) liquid product containing Lacticaseibacillus paracasei, Lentilactobacillus buchneri, and Lacticaseibacillus casei, all formerly known as Lactobacillus. Fresh faecal samples were manually taken from the rectum of all calves, and gross necropsy was performed on the forestomachs and gastrointestinal tracts. Bacterial DNA was extracted from frozen faecal samples for 16S rRNA gene amplicon sequencing. Calves in the TRT group had greater live weights (p = 0.02) at weaning compared with calves in the CON group (mean = 69.18 kg, SD = 13.37 kg). The average daily live weight gain (ADG) and total feed intake were similar between the two groups. Calves in the TRT group had greater duodenum, abomasum, and reticulum weights (p = 0.05). Rumen and intestinal development (p < 0.05) and faecal microbial diversity (p < 0.05) were more pronounced in the TRT group. The relative abundances of eight genera differed (p < 0.001) between the groups. Supplementing calves with the LAB-based DFM increased live weight at weaning and had a more pronounced effect on the development of rumen and the gastrointestinal tract and on microbiota diversity and evenness. Future work is needed to better understand the potential association of LAB-DFM products on gut mucosa-associated microbiota
Fusarium pseudograminearum infected wheat lines vary in disease severity and gas exchange response under different watering regimes
Get PDFCrown rot (CR; Fusarium pseudograminearum) is a serious disease in winter cereals. Soil type, temperature, nutrients, water availability and stubble-borne inoculum levels play major roles in determining disease severity. This paper reports the impact of two different watering regimes on the disease severity and gas exchange of F. pseudograminearum infected bread wheat for the first time. Fusarium pseudograminearum inoculated and noninoculated genotypes with different susceptibility to CR were watered to either field capacity or a reduced watering regime in three controlled environment experiments. Rate of photosynthesis, stomatal conductance, internal CO2 concentration and transpiration rate were measured using a portable photosynthesis system, together with disease severity of leaf sheaths at 28 days after planting. Significant differences in disease severity were reported between watering treatments with reduction in CR symptoms in the partially resistant genotypes in the reduced water treatment. Photosynthesis, stomatal conductance and transpiration rate were significantly decreased across most genotypes when inoculated with F. pseudograminearum. Differences in gas exchange between inoculum treatments were more evident in plants watered to field capacity. Water availability has been reported to be one of the crucial factors for initiating F. pseudograminearum infection and subsequent development of CR disease. This research demonstrates significant variation in genotype-related responses to the complex interactions of F. pseudograminearum infection and water treatment, with a negative impact of both limited soil water availability and CR disease severity on plant gas exchange in bread wheat
Crop Domestication in the Asia Pacific Region: A review
No full textUnderstanding crop domestication provides a basis for ongoing genetic improvement of crops, especially in the utilization of wild crop relatives as a source of new variation and may guide the domestication of new crops. The Asia Pacific region is home to most of the world’s human population and is a region in which many important crops were domesticated. Here we review the domestication of banana, citrus, coconut, macadamia, mango, millet, mungbean, rice, sugarcane and taro in the Asia Pacific region. These examples illustrate the importance of this region in the development of agriculture. The challenges of conservation of the genetic resources for these crops are exacerbated by the large human population and rapid economic development in the region. Advances in genetic technologies provide an opportunity for accelerated genetic improvement of these crops and the domestication of new crops
Monitoring guidelines to quantify nitrogen removal in vegetated water treatment systems (constructed treatment wetlands and vegetated drains)
Get PDFThis document provides guidance on designing water monitoring programs for calculating nitrogen removal by vegetated water treatment systems, including constructed treatment wetlands or vegetated drains. The document focuses on monitoring of vegetated water treatment systems used to reduce nitrogen leaving farms prior to entering natural waterways and wetlands in tropical and sub-tropical Queensland. It aims to enable estimation of nitrogen reduction as accurately as possible within the constraints of monitoring in highly variable environments.
This document aims to provide consistency in monitoring approaches, enabling comparison of different vegetated water treatment systems and synthesis of information across different projects and sites to further knowledge on the performance (and limitations) of vegetated water treatment systems in different climatic regions, farm types and water regimes. The target audience includes research personnel, natural resource managers and land managers interested in monitoring vegetated water treatment systems to assess water quality improvement.
The document is written with the specific conditions and constraints of agricultural production areas in mind. Although vegetated water treatment systems are also used to treat urban stormwater and wastewater such as treated sewage effluent, the design, operating environment, and monitoring budget can be different. The principles in these guidelines can be adapted to these other land uses, although the objective of the vegetated water treatment system, flow regime(s) and nitrogen form(s) may be different thereby influencing the purpose of the monitoring project.
The methods outlined in this document have been compiled from methodologies described in both peer-reviewed publications and reports, together with technical input and advice from scientists and natural resource management officers involved in implementing and monitoring vegetated water treatment systems in Queensland. As monitoring methods, technologies and equipment are constantly evolving, the reader should undertake their own investigations in designing the monitoring program to ensure it meets the specific purpose of the monitoring project.
Detailed information on different types of vegetated water treatment systems and treatment processes are available on the Queensland Government WetlandInfo website wetlandinfo.des.qld.gov.au
Cost–benefit analysis of ecosystem modeling to support fisheries management
No full textMathematical and statistical models underlie many of the world's most important fisheries management decisions. Since the 19th century, difficulty calibrating and fitting such models has been used to justify the selection of simple, stationary, single-species models to aid tactical fisheries management decisions. Whereas these justifications are reasonable, it is imperative that we quantify the value of different levels of model complexity for supporting fisheries management, especially given a changing climate, where old methodologies may no longer perform as well as in the past. Here we argue that cost-benefit analysis is an ideal lens to assess the value of model complexity in fisheries management. While some studies have reported the benefits of model complexity in fisheries, modeling costs are rarely considered. In the absence of cost data in the literature, we report, as a starting point, relative costs of single-species stock assessment and marine ecosystem models from two Australian organizations. We found that costs varied by two orders of magnitude, and that ecosystem model costs increased with model complexity. Using these costs, we walk through a hypothetical example of cost-benefit analysis. The demonstration is intended to catalyze the reporting of modeling costs and benefits
Modelling unseen flow pathways of water and contaminants in the Wet Tropics: the role of alluvial palaeochannels
Get PDFNutrients from agriculture in catchments draining to the Great Barrier Reef (GBR) are a stressor of this important ecosystem. Current GBR catchment models do not mechanistically link movement of nutrients from paddocks to rivers. An understanding of these water and nutrient flow pathways is crucial in any attempt to model and manage the GBR catchments. Conduits of water transport include surface drains and subsurface features such as palaeochannels. Palaeochannels are a common feature in alluvial landscapes, representing old river or stream beds that are often filled with coarse in-fill material which make them ideal water storage zones and conduits of water movement, either by recharging surrounding ground water (GW) or exchanging water with surface drainage networks (e.g., Keen et al., 2007, Owen & Dahlin, 2010, McLachlan et al., 2017). Their presence results in heterogeneity of soil and aquifer properties, which need to be accounted for in any attempt to assess water and nutrient transport in these flat agricultural landscapes
Stock assessment of Queensland east coast prickly redfish, herrmanni curryfish and vastus curryfish with data to December 2023
No full textPrickly redfish, herrmanni curryfish and vastus curryfish are species of sea cucumber from the family Stichopodidae. All three species have a broad Indo-Pacific distribution and are found in multiple countries with coral reef ecosystems. All three species occur across the GBR but at varying depth ranges: 10-30 m for prickly redfish, 0-25 m for herrmanni curryfish and 0-8 m for vastus curryfish.
This is the first stock assessment conducted on Queensland east coast prickly redfish, herrmanni curryfish and vastus curryfish by Fisheries Queensland.
All assessment inputs and outputs are referenced on a calendar year basis (that is, ‘2023’ means January 2023–December 2023).
This assessment used a one-sex age-structured population model and a delay-difference model which led to similar results. The outputs of the age-structured model are presented as the main results for all three species in this assessment.
The assessment incorporated commercial catch and effort data spanning 1995 to 2023 as well as length composition data and estimates of absolute abundance from recent surveys undertaken in 2023. No recreational or Indigenous catch data were available and catches from these sectors are considered negligible. There are no discards due to the highly selective nature of the fishery.
Several Stock Synthesis scenarios were run to examine the implications of different fixed model parameters such as steepness (h) and natural mortality (M) on model outcomes. All scenarios were optimised using Markov chain Monte Carlo (MCMC) to better explore the robustness of the models. From these exploratory scenarios a final base case was chosen for each species. The base case Stock Synthesis results indicated that the biomass ratio of prickly redfish at the beginning of 2024 was between 73% and 116% of unfished levels. The base case Stock Synthesis results indicated that the biomass ratio of herrmanni curryfish at the beginning of 2024 was between 81% and 141% of unfished levels. The base case Stock Synthesis results indicated that the biomass ratio of vastus curryfish at the beginning of 2024 was between 65% and 124% of unfished levels
Antagonistic Effect of Microplastic Polyvinyl Chloride and Nitrification Inhibitor on Soil Nitrous Oxide Emission: An Overlooked Risk of Microplastic to the Agrochemical Effectiveness
No full textMicroplastics are widely persistent in agricultural ecosystems and may affect soil nitrous oxide (N2O) emissions. Nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) is applied to decelerate nitrification and reduce soil N2O emission. Nevertheless, the interactive effects of nitrification inhibitors and microplastics on soil N2O emissions have not been investigated. Sole DMPP, polyvinyl chloride (PVC), and polystyrene (PS) substantially reduced agricultural soil N2O emission rates by 25.93%, 69.04%, and 73.89%, respectively. Nevertheless, PVC and DMPP had antagonistic effects on the N2O emission rates. The observed reductions in N2O emissions could be attributed to variations in soil oxygen availability, electron transport system activities, and Firmicutes, nap, and GDH genes. Moreover, the DMPP, PVC, and PS alone or copresences significantly enhanced the soil ecosystem multifunctionality (EMF). The findings shed light on the role of microplastics in soil N2O emission, EMF, and the microbial community, expanding the understanding of microplastics’ effects on agrochemical effectiveness